OP10.03: Fetal post‐mortem MRI examination: the potential of “black bone” imaging sequences for skeletal abnormalities

Post-mortem MRI examinations are being used increasingly due to the growing reluctance of parents to pathologic examinations and the limited availability of competent pathologists. However, one of the limitations of MRI is the examination of the skeleton. We aimed to determine the potential of post-mortem « black bone » (BB) MRI imaging sequence as an alternative to conventional radiography in the examination of normal and pathological skeleton in fetuses. Sixty fetuses from TOP underwent BB MRI imaging sequences. All scans were performed on a 1.5 T MRI. BB imaging sequences was subsequently used to develop 3D reformats of the skeleton. Postmortem magnetic resonance images were reported blinded to the radiology finding. Conventional autopsies and radiography were performed blinded to the MRI findings. GA and prenatal investigation results were known before MRI and autopsy. Skeletal abnormalities were found in 19/60 (31.6%). Median GA was 25 week of gestation (range 16-36). Median time interval between birth and MRI was 17 hours (range 2-27). Overall sensitivity and specificity of BB MRI for skeletal pathology were 89.4% and 97.5% with positive and negative predictive values of 94.4% and 95.2%, respectively. Skeletal dysplasia was identified on BB MRI in 6/7 cases (85%). 17 correct positive skeletal diagnoses were made, including 6 of skeletal dysplasias. Two diagnostics at autopsy were not identified on BB MRI, including one vertebral abnormality and one skeletal dysplasia at 16 GA. The main limitation of fetal BB MRI sequences was the diagnosis of craniosynostosis due to the tangle of the skull bones in post-mortem. One case of metopic synostosis was not diagnosed on BB MRI. 3D images of sutures were successfully made in this case. Post-mortem « black bone » MRI imaging sequences offers a radiation-free method of imaging the fetal skeleton. 2D and 3D imaging could be a potential alternative to radiography and could allow post-mortem analysis of the fetus to be extended to include bone anomalies.